Miniature symmetrical contact polarized relay



Feb. 2, 1965 TAKASHI OKAMOTO ETAL MINIATURE SYMMETRICAL CONTACT POLARIZED RELAY Filed Jan. 3, 1963 3 Sheets-Sheet l Feb. 2, 1965 TAKASHI OKAMOTO ETAL 3,168,628 MINIATURE SYMMETRICAL CONTACT POLARIZED RELAY Filed Jan. 3, 1963 3 Sheets-Sheet 2 relay,

United States Patent 3,168,628 MINIATURE SYMMETRICAL CONTACT POLARIZED RELAY Takashi Okamoto, Tokyo, and Atsushi Ishii, Kawasaki, Japan, assignors to Fuji Tsushinki Seizo Kabushiki Kaisha, Kawasaki, Japan, a corporation of Japan Filed Jan. 3, 1963, Ser. No. 249,263 Claims priority, application Japan, Jan. 16, 1962, 37/ 3,205 9 Claims. (Cl. 200-93) Our invention relates to miniature polarized relays particularly for signal transmission such as telegraph repetition and ringer circuit control in carrier telephony.

An object of the invention is to provide a polarized for signal transmission purposes, having a combination of higher sensitivity and better dynamic characteristics than has hitherto been obtainable with relays of this kind. Particularly it is an object to provide a highsensitivity miniature polarized relay having a symmetrical contact ratio of the right and left contacts when actuated by alternating current, having contacts which are free from chattering upon opening and closing, and having characteristics whiich remain stable throughout repeated operation.

Another object of the invention is to provide a miniature polarized relay of high sensitivity and good dynamic characteristics wherein signal distortion is minimized despite frequent operation to an extent hitherto unobtainable.

Yet another object of the invention is to provide a miniature polarized relay of simple construction having the before-mentioned advantages which can nevertheless be assembled with ease.

The invention will be explained by means of the following description in connection with the accompanying drawing wherein:

FIG. 1 is a perspective view of the assembled polarized relay according to the invention;

FIG. 2 is a partially exploded view of the relay according to FIG. 1 showing four subassemblies in their unexploded perspective form, the assemblies constituting from top to bottom the excitation coil of the relay, the armature assembly of the relay, the heel or yoke assembly of the relay, and the relay base;

FIG. 3 is an exploded view of the heel or yoke assembly in FIGS. 1 and 2;

FIG. 4 is an exploded view of the relay base showing in particular detail the contact mechanism associated therewith;

FIG. 5 is a plan view of the relay base in FIGS. 1 and 2;

FIG. 6 is an exploded view of the armature assembly according to FIGS. 1 and 2;

FIG. 7a is a simplified schematic diagram of the heel assembly combined with the excitation coil and the armature assembly in perspective form for illustrating the operation of the present invention;

FIG. 7b is a cross-sectional plan view of the schematic illustration in FIG. 7a for purposes of explaining the operation of the invention;

FIG. 8 is a graph of the contact-ratio and bias-distortion characteristic curves of the relay according to FIG. 1;

FIG. 9 is a graph showing the contact-ratio curves and bias-distortion curves with respect to frequency in the relay according to FIG. 1; and

FIG. 10 is a graph showing further characteristic curves of the relay according to the invention.

As can be seen from FIGS. 1 and 2, the polarized relay according to the invention comprises a relay base generally designated D including a contact mechanism assembly, a heel or yoke assembly formed of punched plates seated upon the relay base and generally designated C,

pieces 8 and 9. One

3,168,628 Patented Feb. 2, 1965 and armature assembly generally designated B which is embraced by the heel assembly and includes a permanent magnet, and an exciting coil generally designated A supported by the heel piece assembly. According to the invention, each of these major components is assembled individually and then fabricated into a single polarized relay. The individual subassemblies A, B, C and D are first described individually, their manner of assembly being disclosed thereafter.

The exciting coil assembly A consists of an exciting coil 1 of an insulated wire such as covered copper wire, formed around an iron core 2 with both ends of the latter exposed. The coil 1 is embedded in an adhesive or epoxy resin to prevent disfigurement and loose strands. According to this embodiment of the invention, the exciting coil does not function with a bobbin or moving core so that the wire may be wound into a compact body.

The armature assembly B appears assembled in FIG. 2, but in more detail in an exploded view in FIG. 6. It comprises a permanent-magnet armature formed of two thin oblong plates welded together for good electrical contact and mechanical soundness. The plates 3 are magnetized in the longitudinal direction after being coupled. They embrace at their longitudinal center a fulcrum spring 4 forming a cross member and constructed of a high grade elastic material such as beryllium-copper alloy and provided with four grooves forming two neck 4a. A pair of C-shaped non-magnetic metal holders, preferably of nickel, silver or brass, are soldered, welded or screwed together in face-to-face relationship to provide electrical as well as mechanical contact about the upper and lower extremes of the fulcrum spring 4, sandwiching these extremes between them. Thus the holders 5 support elastically the armature 3, 3 for resilient movement about their transverse axes by means of the fulcrum spring 4. The armature 3, 3 can then swivel about the spring 4 against the tension created in the narrowed or necked portion 4a. A pair of downwardly extending tungsten or platinumiridium alloy contact bars 6 are secured electrically to the respective ends of the magnet armature 3, 3 comprised of plates 3.

The heel assembly or yoke assembly of FIG. 2 appears as an exploded view in FIG. 3. Two similarly shaped Permalloy or super-Permalloy magnetic metal plates formed by punching are bent to form heel pieces or yoke I end of each yoke piece extends in an L-shaped elongation 14 terminating in forked members 15. The yoke pieces 8, 9 bulge in the mid-section, and face each other, engaging between their opposing ends the tops of two hollow cross-shaped supports 7, made of non-magnetic material such as nickel, silver or brass. Two pairs of screw holes, one in each yoke piece, serve to receive each of the four screws 10 made of 'magnetic material such as Permalloy or super-Permalloy.

As will be described later, these screws serve as magnetic poles. Two pairs of screw holes near the bottom of each heel piece are adapted to receive adjusting screws 11 of nickel alloy having at their respective inwardly facing tips welded glass beads 12. The lower portion of the end supports 7 constitutes a tongue 33 for affixing the heel piece assembly into the relay base. A hollowed out punched bore 13 in the support 7 permits adjusting the contact positions as will be later described.

The yoke pieces 8 and 9 together with the supports 7 are fabricated into a frame as shown in FIG. 2 and joined together both electrically and mechanically by means of welding or soldering. compactness is accomplished by locating each end of the heel pieces 8 and 9 as well as the elongations 14 upon the step formed by the cross member of the support 7, the thickness of the punched metal in the heel pieces 8 and 9 corresponding to the depth of the step. The elongations 14 are twisted so as to form an approximate right angle relative to the heel pieces and confront each other across the length of the heel pieces. The lines on the bifurcated portion 15 of each member 14 serve to receive between them respective exposed ends of the core 2 about which is wound the exciting coil 1. The core is coupled to the heel pieces both mechanically and magnetically.

The contact mechanism of the relay base D is shown in exploded view in FIG. 4 and consists of a pair of contact springs 18 and 18', contact positions springs 19 and 19 and friction springs 20 and 20 shaped as shown. As seen in FIG. 2, the contact springs 18, 18' and the friction springs 20, 20 are fastened to respective position springs 19, 19' by means of spot Welding, the contact positioning springs being fixed at one end to terminal pins 24 and 27 penetrating the relay base support or plate 17, by means of spot Welds. A space is provided between the free ends of the respective contact springs 18, 18' and the positioning springs 19, 19' so they will not touch each other. The friction springs 29, 20 frictionally engage the respective springs 18, 18'.

Two contact bars 32 are each welded to respective free ends of the contact springs 18, 18. The springs 18, 13, 19, 19, and 20, 20' are mounted with their planes perpendicular to the relay plate 17 and with at least one edge parallel to the relay base plate, thereby providing a contact structure requiring little space. The relay base support or plate 17 is comprised of metal such as soft steel having respective vertical cylindrical openings through which pass respective ones of ten terminal pins 21 to 30 which are insulatingly secured to the plate 17 by means of glass bonding. A pair of recesses or dents at opposite ends of the rectangular plate 17 are adapted to receive the tongues 33 of the support 7. The terminal pins 24, 27 possess bent tops in the form of an L-shape for supporting the contact positioning springs 19, 19' which are suitably secured thereto. Thus the terminal pins 24 and 27 serve both as supports and contact mechanism as well as serving as electrical connectors for the contact springs 18, 18. The upper end of the terminal pin 23 forms a curved electrical connection with the relay base plate 17 to which it is soldered r spot-welded. Similarly the supports 7, heel pieces 8, 9, holders 5, fulcrum spring 4 and armature plates 3 all are ultimately grounded to the relay base plate 17. Other insulated pins serve as lead terminals for the exciting coil 1.

The above components are assembled so that the annature assembly B is supported by the yoke assembly C. This is accomplished by sealing the holders of the armature assembly B between the bulged section of the yoke pieces 8 and 9, as shown in FIG. 1. Then the yoke pieces 8 and 9 are fastened to the holders 5 by such means as soldering, welding or screws. The armature stroke is adjusted for a specified length and symmetry about its central position by setting the four magnetic pole screws 10. The yoke assembly C is fixed to the relay base plate 17 by fitting the tongues 33 of the supports 7 in the indents 31 of the base and welding them together. The glass beads 12 at the tip of the screws 11 near the bottom edge of the yoke piece 8 then are set for contact with the free ends of the springs 19, 19'. The armature contacts 6 are set to confront the contacts 32 mounted on the free ends of the contact springs 18, 18'. Fastened to the yoke pieces 8 and 9 is the exciting coil 1, with both ends thereof fitting between the bifurcated ends 15 in the elongations 14 of the heel pieces 8, 9. The lead wires for the coil 1 are connected to the designated terminal pin on the relay base plate 17.

After assembly of the portions A, B, C and D, the armature 3, 3 is energized at a predetermined operating intensity and the contact bars 32 are properly positioned by setting the adjusting screws 11. In this adjustment the punched bores 13 permit observing the contact positions. Finally the exciting coil, the armature assembly, the heel piece assembly and the contact mechanism are covered by a metal case (not illustrated), which is fixed to the relay base preferably by soldering. In addition the case is evacuated, filled with an inactive gas and sealed hermetically. The exposed surfaces of the case and the relay base are then insulated electrically by coating them with an insulating varnish such as polyurethane. Thus the completed polarized relay can be plugged into a multijack or a printed circuit board by means of the terminal pins 21 to 30.

The operation of the polarized relay in FIG. 1 may be understood from FIGS. 7a and 7b which are simplified illustrations of the magnetic circuit for the relay. Assuming that the armature 3 is magnetized as shown in the figures, the magnetic fluxes flow along the respective paths and When the exciting coil 1 is energized by a signal current it causes excitation magnetic fluxes and p Flux opposes 5 at 1' and aids p at r while flux aids at r and opposes at r Accordingly, the armature 3 rotates clockwise. If the exciting current is reversed, the armature in turn revolves counterclockwise.

With regard to current flow, operation is as follows. Current through the contact bars 6 of the armature 3 is also carried through medium of the terminal pin 23, the relay base plate 17, the pole piece assembly and the armature assembly. As described before, the contact bars 5 are connected electrically to the holders 5 through tr e armature 3 and the fulcrum spring 4. Also the yoke pieces 8 and 9, the supports 7 and the relay base 17 are alike made of a metallic material and mutually coupled electrically. Electrical continuity is also established among the yoke pieces 8 and 9, the holders 5, the terminal pin 23 and the relay base plate 17 Consequently, the terminal pin 23 and the contact bars 6 are electrically connected together through medium of these components, thus dispensing with any specific wiring connection.

The contact mechanism seated on the relay base D consists, as described before, of contact springs 18 and 18', contact positioning springs 19, 19' and friction springs 20, 2t) and is shown in exploded view in FIG. 6. Springs 18, 18' are brought into respective contact with springs 20, 20 at their free ends to produce a proper contact pressure. At every make and break as a result of the rods 6 engaging the contact bars 32 springs 18, 18' and 20, 20' displace themselves slightly by sliding on each other. In this manner they absorb the energy otherwise causative of chattering, thus assuring favorable characteristics in response to a wide range of driving current and frequency. The springs 18, 18' and 20, 20' are held by the positioning springs 19, 19' and, through the latter, by the terminal pins 24 and 27. Since the screws 11 can displace the springs 19, 19 slightly, the contact separation can be adjusted without changing the relative positions of the contact springs 18, 18' and the friction springs 20, 20'. Thus it is possible to set the contact pressure selectively, thereby reducing the otherwise-occurring bias distortion as well as improving the freqeuncy characteristics.

The chattering prevention device utilizing the friction springs 20, 20' also help lengthen the service life of the relay. As a rule the miniaturization of a relay involves decreasing the size of its contact springs. Prevention of chattering in a relay usually requires a considerable flexibility for the contact springs. However, this makes them subject to creep or fatigue. In accordance with the invention, the friction springs serve to make the contact springs stiff, thereby reducing the variation of the relay characteristics resulting from creep or aging, and ensuring a long life for the relay. The durability of the relay is also supplemented by the permanent magnet armature. As shown in FIGS. 2, 6, the armature 3, 3 has an oblong shape, surrounded by the yoke pieces. Therefore, it is less subject than otherwise to the influences of external magnetic fields and consequently possesses excellent aging characteristics. In addition, the hermetically sealed case and inactive gas fill totally eliminate the cause for contact faults, thus securing the relay a satisfactory working condition lasting for a long period. Each of the contact bars 6 and 32 attached respectively to the armature 3 and to the contact springs 18, 18' has a flat contact surface for freedom from abrasion that might cause deterioration in the performance characteristics.

As described, the two permanent magnet plates 3 forming the armature are held between the heel pieces 8 and 9 through the medium of the fulcrum spring 4 and the two C-shaped holders 5. This secures support of the armature by a relatively simple mechanism. Since the fulcrum spring 4 is positioned in the middle of the armature so that the armature is made symmetrical with re gard to the narrow section of the fulcrum spring 4 serving as the axis of rotation, no change is caused in the performance characteristics according to the direction in which the relay is fixed. In addition, the armature has a very small moment of inertia and accordingly suffers little bias distortion. All these advantages plus the light weight of the armature serve to raise the working speed of the latter, thus securing its good contact. Also, the resonance frequency of the armature is raised considerably resulting in improvement of the relay frequency response.

FIG; 8 shows the dynamic characteristic curves of the I polarized relay in FIG. 1 obtained through a series of experiments for the case where the relay is driven by a 25 c.p.s. alternating current input. As shown in FIG. 8, the contact ratio exceeds 90%, while the bias distortion remains within the range of :t3%.

FIG. 9 illustrates the frequency characteristics of the relay when the driving electromagnetic force is set at 25 ampere-turns. The figure shows that the contact ratio is kept above 90% at a frequency up to 100 c.p.s. and that the bias distortion remains within 15% at a frequency below 150 c.p.s. and between 200 c.p.s. and 400 c.p.s., except that it rises to some extent in the neighborhood of 200 c.p.s.

FIG. 10 shows an experimentally obtained curve of the dynamic aging characteristic of the relay in FIG. 1. As shown in FIG. 10, the operating current is kept virtually constant throughout repetition of actuation amounting to about 300 million times.

While an embodiment of the invention has been shown in detail it will be obvious to those skilled in the art that the invention may be practiced otherwise without departing from the scope of the invention.

We claim:

1. A polarized relay comprising magnetic excitation means, an elongated permanent-magnet armature having contacts at each end, spring means pivotally supporting the armature at its center and biasing the armature into a central position, a yoke assembly supporting said excitation means and said spring means and having two magnetizable yoke pieces extending along the armature on opposite sides thereof and spaced therefrom.

2. A polarized relay comprising magnetic excitation means, an elongated permanent-magnet armature having contacts at each end, spring means pivotally supporting the armature at its center and biasing the armature into a central position, a yoke assembly supporting said excitation means and said spring means and having two magnetizable yoke pieces extending along the armature on opposite sides thereof and spaced therefrom, a base supporting the yoke assembly, a pair of contact springs mounted on the base and insulated relative to said yoke assembly, said springs having contact terminals located on the same side of said armature in the vicinity of said contacts.

3. A polarized relay comprising magnetic excitation means, an elongated permanent-magnet armature having contacts at each end, spring means pivotally supporting the armature at its center and biasing the armature into a central position, a yoke assembly supporting said excitation means and said spring means and having two magnetizable yoke pieces extending along the armature on opposite sides thereof and spaced therefrom, a base supporting the yoke assembly, a pair of contact springs mounted on the base and insulated relative to said yoke assembly, said springs having contact terminals located on the same side of said armature in the vicinity of said contacts, friction springs frictionally engaging said contact springs and mounted on said base for absorbing the impact of said contacts on said contact springs.

4. A polarized relay comprising an iron core; an ex citing coil wound on said core; an armature assembly including a permanent-magnet armature having contacts at both ends, a fulcrum spring resiliently supporting said armature in the center and allowing the latter to rotate, and two C-shaped non-magnetic holders supporting said fulcrum spring; a yoke assembly including yoke pieces of a similar shape and two non-magnetic metal supports for forming a frame; a base having terminal pins; and a contact assembly arranged parallel with the said base and including two contact springs having contact members and respective contact positioning springs supporting said contact springs and connecting said contact springs to individual ones of said terminal pins; extensions on said yoke pieces for coupling said iron core thereto magnetically and mechanically at both ends, said armature assembly being housed in the frame formed by said yoke pieces and said supports so that the said yoke pieces hold the said armature assembly between both of them, said yoke piece assembly being coupled to the said relay base, said contacts provided at both ends of the said armature confronting said contact members of said contact springs.

5. A polarized relay comprising an iron core; an exciting coil wound on said core; an armature assembly including a permanent-magnet armature having contacts at both ends, a fulcrum spring resiliently supporting said armature in the center and allowing the latter to rotate, and two C-shaped non-magnetic holders supporting said fulcrum spring; a yoke assembly including yoke pieces of a similar shape and two non-magnetic metal supports for forming a frame; a base having terminal pins; and a contact assembly arranged parallel with the said base and including two contact springs having contact members and respective contact positioning springs supporting said contact springs and connecting said contact springs to individual ones of said terminal pins; extensions on said yoke pieces for coupling said iron core thereto magnetically and mechanically at both ends, said armature assembly being housed in the frame formed by said yoke pieces and said supports so that the said yoke pieces hold the said armature assembly between both of them, said yoke piece assembly being coupled to the said relay base, said contacts provided at both ends of the said armature confronting said contact members of said contact springs, said armature including two oblong permanent magnet plates secured together with the said fulcrum spring interposed at their longitudinal center, said fulcrum spring being held between the ends of said C-shaped nonmagnetic holders, electric connection to said contacts being provided through said holders, said fulcrum spring and said armature.

6. A polarized relay comprising an iron core; an exciting coil wound on said core; an armature assembly including a permanent-magnet armature having contacts at both ends, a fulcrum spring resiliently supporting said armature in the center and allowing the latter to rotate, and two C-shaped non-magnetic holders supporting said fulcrum spring; a yoke assembly including yoke pieces of a similar shape and two non-magnetic metal supports for forming a frame; a base having terminal pins; and a contact assembly arranged parallel with the said base and including two contact springs having contact members and respective contact positioning springs supporting said contact springs and connecting said contact springs to individual ones of said terminal pins; extensions on said yoke pieces for coupling said iron core thereto magnetically and mechani cally at both ends, said armature assembly being housed in the frame formed by said yoke pieces and said supports so that the said yoke pieces hold the said armature assembly between both of them, yoke piece assembly being coupled to the said relay base, said contacts provided at both ends of the said armature and confronting said contact members of said contact springs, said yoke pieces each being bulged outward in the center section, two screws made of magnetic material in said pieces extending into said frame and functioning as magnetic poles, and the said yoke pieces supporting said screws so that they confront each other and interpose an adjustable gap for the said armature to rotate in, said armature assembly being located in said frame and fixed mechanically to the bulged sections of the said yoke pieces, both ends of the said armature being positioned in the gap between said pole screws.

7. A polarized relay as in claim 4, wherein one of the said yoke pieces includes adjustable screws insulated at their respective tips, confronting the free ends of the said contact positioning springs for regulating the position of the contacts on the said contact springs.

8. A polarized relay comprising an iron core; an exciting coil wound on said core; an armature assembly including a permanent-magnet armature having contacts at both ends, a fulcrum spring resiliently supporting said armature in the center and allowing the latter to rotate, and two C-shaped non-magnetic holders supporting said .fulcrum spring; a yoke assembly including yoke pieces of a similar shape and two non-magnetic metal supports for forming a frame; a base having terminal pins; and a contact assembly arranged parallel with the said 'base vmagnetically and mechanically at both ends, said armature assembly being housed in the frame formed by said yoke pieces and said supports so that the said yoke pieces hold the said armature assembly between both of them, said yoke piece asssembly being coupled to the said relay base, said contacts provided at both ends of the said armature confronting said contact members of said contact springs, said contact mechanism further including friction springs, said contact spring and said friction spring being coupled to the contact positioning springs supported thereby upon said terminal pins on the said relay base, the respective free ends of the contact and positioning springs being separated from each other, whereas the tree ends of the friction springs touch those of the contact springs with a fixed pressure to slide thereon at every makeand break of the contacts.

'9. A polarized relay as in claim 4, wherein the said relay base is comprised of a metalmaterial and connected electrically with one of said terminal pins so that current supply to the contacts of the said armature can be elfected successively through thesaid terminal pins, the said relay base, :said yoke assembly, andthe holders, the fulcrum spring and the armature, a case that fits into said relay base covering the entire assembly and thus hermetically sealing the relay and insulation coating upon the external surfaces of said base and case.

:No references cited. 

1. A POLARIZED RELAY COMPRISING MAGNETIC EXCITATION MEANS, AN ELONGATED PERMANENT-MAGNET ARMATURE HAVING CONTACTS AT EACH END, SPRING MEANS PIVOTALLY SUPPORTING THE ARMATURE AT ITS CENTER AND BIASING THE ARMATURE INTO A CENTRAL POSITION, A YOKE ASSEMBLY SUPPORTING SAID EXCITATION MEANS AND SAID SPRING MEANS AND HAVING TWO MAGNETIZABLE YOKE PIECES EXTENDING ALONG THE ARAMTURE ON OPPOSITE SIDES THEREOF AND SPACED THEREFROM. 